1. Field of the Invention
The present invention relates to a sun-ray tracking system in which tow rows of sun-ray collecting units are arranged along first turning axes, respectively, with each row having a plurality of the units, and the rows of collecting units can be turned about the first turning axes and also about second turning axes perpendicular to the first turning axes.
2. Description of the Related Art
Such a sun-ray tracking system is already known, for example, from Japanese Patent Publication No. 57-10337.
In the above known sun-ray tracking system, the sun-ray collecting units turnable about the second turning axes are mounted at a plurality of places spaced apart from one another in an axial direction of a main shaft with its center matched with the first turning axis, in such a manner that the units are aligned on opposite sides of the main shaft. A motor is connected to one end of a driving shaft extending in parallel to the first turning axis, and sector-shaped worm wheels connected respectively to the sun-ray collecting units are meshed with a plurality of worms provided on the driving shaft. For this reason, each of the sun-ray collecting units is turned to describe a turning locus at a location spaced apart from the center of the main shaft by turning movement of the main shaft about its axis, i.e., the first turning axis, resulting in an increased limitation for a placing area. Especially, when the main shaft is turned to turn the sun-ray collecting units in an east-west direction, the turning angle is relatively increased. Therefore, an unoccupied space required for turning movement of each of the sun-ray collecting units is increased in size, and it is difficult to place the sun-ray tracking system, for example, on a roof of a house or building.
For the purpose of solving such a problem, it is conceived that a plurality of sun-ray collecting units are supported, for turning movement about each of second turning axes, on each of a pair of turning frames which are turnable about a pair of first turning axes established in parallel to each other. However, if a driving mechanism including a worm and a worm wheel as in the prior art is used in order to turn the sun-ray collecting units about the second turning axes, a drive source such as a motor or the like is required for each turning frame, whereby an increase in cost is brought about, and it is necessary to accurately control both the drive sources, so that no operational difference is produced between both the turning frames.